Positioning process and system

ABSTRACT

A process and device are disclosed for positioning devices for temporarily fixing a workpiece in any desired angular position in a three-dimensional working space of which the coordinates are known, in particular when the workpiece requires a multidimensional support A computer-controlled machine with a tool movable in the direction of all co-ordinates is used for that purpose, together with a freely movable, vertically adjustable device or supporting column mounted on a base plate and upon which the supporting device for the multidimensional support of the workpiece is positioned. Based on the tool geometry or a C.A.D. programme, a coupling or an appropriately designed measurement head of a measurement machine is fixed on the tool with respect to a calculated plane of reference for the tool and to an axis inclined in relation thereto which cuts the plane of reference. The coupling parts designed as a coupling are then brought to a position at the tool or device which corresponds to the plane of reference, either directly by means of driven coupling parts or after a previous adjustment on an adjustment device placed on the base plate. The tool or measurement head is then moved into the precalculated position in space of the support of the workpiece and a supporting column with a corresponding supporting device is aligned with the position of the tool. The disclosed process steps and the positioning systems used to implement the process enable a three-dimensional supporting surface to be provided within a few minutes for a workpiece to be measured or machined, with an accuracy of more than 0.1 mm.

BACKGROUND OF THE INVENTION

1. Field of the invention

The invention relates to a method and a device for positioning aclamping device for workpieces within a predetermined working space.

The invention is described hereafter essentially with reference to ameasuring machine and a positioning and clamping system provided for it,but is not restricted to measuring machines of this kind, instead beingcapable of being used in the same way for positioning systems with theaid of triaxially controllable robot systems for a tool. The system is,to that extent, suitable both for measuring machines and for processingmachines.

2. Discussion of the Prior Art

Workpieces of any contour, in order to be accurately measured orprocessed, must be temporarily fixed within a specific three-dimensionalspace corresponding to the range of the measuring system or processingmachine. Where measuring machines are concerned, this space is delimitedin the plane by a measuring plate, a measuring table or a clampingplate, and the third dimension is determined by the range of themeasuring tracer on a measuring bridge or a measuring boom (DE 22 32 858A2 and DE 37 17 541 A1).

Adjustable columns, which can be locked with pin-point accuracy on theclamping plate, serve as clamping devices or seating columns for theworkpiece. These include devices, such as are known, for example, fromDE 44 24 765 A1 or U.S. Pat. No. 4,848,005.

A complete software-controlled measuring machine “TYPHOON” with a “FiveUnique” clamping device was published in a prospectus of the same nameby the company DEA-Brown-Sharpe SpA, Moncalieri, IT.

With the aid of the measuring machines or measuring robot, a referencepoint corresponding to a clamping point of the workpiece is approachedin the three-dimensional measuring space surrounding the workpiece. Asupport or clamping column, which can be fixed on the measuring table,is then placed under this clamping point, as a rule by displacing thecolumn as accurately as possible, manually or mechanically (U.S. Pat.No. 4,848,005), in the horizontal plane (XY-axis) and adjusting itsheight (Z-axis) vertically. The other clamping points are found andfixed in the same way.

A CAD program or a drawing of the workpiece, which are edited forsoftware processing in the measuring machine, serves as an aid. Inaddition, the measuring rod or tracer of the measuring machine isreplaced by a removable centering device which serves as a complementarysimulated workpiece point at the clamping point of the column to bepositioned. The centering device has a coupling element, for example agripper or a ball catch, so that the column to be positioned can becoupled positively. This complicated positioning method is described indetail in DE 195 10 456 A1, as are some clamping means which can be usedfor fixing the workpieces.

Turntables with positioning accuracies of below +/−0.05° absoluteaccuracy, which are equipped with stepping motors or servomotors, arealso known for positioning components at specific angles in one plane.The positioning accuracy is achieved by means of limit switches whichutilize the Hall effect. Turntables of this kind bearing the typedesignation RTM are offered by the company Spindler & Hoyer GmbH & Co,Göttingen, Del.

Measuring columns movable on a measuring plate may be used, according toEP-B-0,216,041 for the automatic detection of individual measuringpoints even of very large components.

It is not possible, with the systems mentioned, to simulate a seatingsurface of any position and extent in the three-dimensional measuringspace, that is to say working space, or to provide for a seating surfaceof this kind a column with a plane or curved clamping surface orotherwise spatial clamping surface; at least not when the position ofthe surface in the space assumes any solid angle which deviates from theangles standardized in grid systems, such as 15°, 30°, 45°, etc.

As regards the details of the clamping elements, centering balls andother details of the measuring machine, measuring plate and columns forthe workpiece seatings and their functioning, reference is made to thepublications mentioned here, and the description of these, by beingquoted, is included in the disclosure of this invention. This appliesinsofar as other systems are not described for preference here.

SUMMARY OF THE INVENTION

The problem on which the invention is based, therefore, is to provideany clamping surface or multidimensional clamping and positioning devicewithin the working space, so that a multidimensional clamping surface orcorrespondingly disposed clamping points for workpieces can be arrangedon a corresponding positioning device.

The invention is based on the notion that, with the previous methods andpositioning systems of the automatic or manual type, only point seatingsor concrete points can be positioned accurately in order to seat theworkpiece. In many cases, the workpiece surface, which serves forseating the workpiece or with which the workpiece is to be fastened toother parts, is not plane or does not have any horizontal extent in theworking space, the coordinates of which are known. In these cases, forexample if a seating surface has any solid angle, punctiform seating ofthe workpiece is inaccurate or leads to inaccurate temporary clamping ofthe workpiece. It was expedient, here, to find an economical, simple andcost-effective solution, using the hitherto conventional robot systemsor measuring machines, in particular an arrangement for the measurementof workpieces. According to the prior art, it is necessary, in order toobtain a spatially arranged seating surface for the workpiece, tomanufacture a special seating means which was capable of being placed onthe punctiform supports, in particular seating columns on baseplates ofmeasuring machines. In this case, there is the problem, inter alia, ofaccurately manufacturing this seating means which, under certaincircumstances, can be used only once. Serious problems are alsopresented by prismatic workpieces or tubular workpieces or similarlyshaped workpiece parts which, for measurement purposes, have to bepositioned temporarily, in any axial position, below a spatial positionknown only from the finished product, or by devices for measuringmethods, which require a controlled distance between a seating means andthe workpiece, so that a uniform outer contour of the workpiece can bedetected by means of a gage.

Proceeding from this, a method was developed for the accuratepositioning of devices, such as seating columns and the like, for thetemporary fixing of the workpiece in a known three-dimensional workingspace. It is presupposed, in this case, that the workpiece requires amultidimensional, that is to say spatially, randomly arranged seatingand the tool or a measuring head with a measuring tracer can approachall the coordinate points, and the machine is equipped with a computer,as is the case, in particular, in three-dimensional measuring machines.The means made available by the measuring machine, such as collisionprotection or the transmission of electric control or power signals, canbe used in the solution proposed here, in that they are employed, via acorresponding coupling system, on the head of the machine, for examplethe measuring head, for example as an exchange element for the measuringtracer. Opposite this measuring machine or processing machine, by whichis meant, for example, a grinding device or a grinding tool and thelike, and also, for example, an erosion tool, is located, as a rule, abaseplate, for example of the measuring plate of the measuring machine,and, on this, a vertically adjustable device freely movable in the X-and Y-axes, usually also designated as seating columns. In the priorart, these seating columns are, as a rule, provided with spherical orsuch like heads, so that the workpiece can be put in place there.

In the solution according to the invention, it is, of course, alsopossible to use such balls or standardized seating points unless,according to the invention, special seating means is to be used, whichtakes into account the multidimensional random spatial position of theworkpiece. According to the invention, the seating column or similardevice is equipped with a first coupling and the tool, that is to saythe head of the machine, is equipped with a corresponding adapter havinga second coupling, said device and said tool being movably connected inrotation through 360°. Each of these couplings consists of at least twocoupling parts which are connected by means of lockable and pivotallymovable intermediate joints, the two couplings temporarily beingindirectly couplable to one another. This coupling may take place bymeans of a spacer piece between the freely movable coupling parts of thedevice and of the tool respectively or the coupling parts consist, attheir free ends, of magnets, for example magnetic plates, which can thusindirectly couple the couplings of the device and of the tool to oneanother.

It is assumed that the workpiece configuration is available as a drawingor CAD program and that the spatial position of the seating surfaces ofthe workpiece can also be converted into coordinate points with the aidof the machine. The multidimensional seating thus determined istransposed to the system of coordinates of the working space and anarithmetic reference plane of the seating is then determined withrespect to the multidimensional seating. This reference plane serves forfixing an axis which intersects this plane and according to which theentire positioning system can be oriented. The outer coupling parts onthe tool are then aligned along the intersecting axis, and fixed, by thelocking of the intermediate joint, and the tool is moved toward thearithmetically determined intersecting axis in the working space at adefined distance from the reference plane. This defined distance servesfor receiving a spacer piece for coupling to the seating column, then tobe aligned with the reference plane, and, if appropriate, forpositioning a clamping means and a seating means on the seating column.After a seating column has been preadjusted approximately in the X- andY-positions and the height (Z-axis) of the corresponding coupling partfor the seating device subsequently to be mounted has then been aligned,the adjacent coupling parts of the device and of the tool are aligned soas to be axially true and are then fixed relative to one another. Thisfixing may take place by the intermediate coupling of a spacer piece ofknown length, while, at the same time, angular differences may becompensated for for the exact adjustment of the seating columns.

On the other hand, it is possible for the free ends of the couplingparts of the couplings to be equipped with magnetic elements which arethen temporarily coupled to one another by means of magnetic forces inthe position of the intersecting axis.

After this fine adjustment and alignment of the seating column or deviceon the baseplate has been carried out, the device is secured both on thebaseplate and in terms of height. The couplings of the device and of thetool can then be uncoupled from the spacer piece, and a seating meanscomplementary with the workpiece seating can be inserted into the thenfreed coupling part of the device or seating column and secured. It mustbe remembered, in this case, that both the spacer piece and the couplingparts are manufactured with high accuracy and have as little play aspossible, so that a repetitive accuracy of <0.1 mm can be guaranteedabsolutely. The workpiece, for example an injection molding, can, as arule, be manufactured with such narrow tolerances, so that acorresponding measuring machine or processing device must, of course,also be produced with similarly narrow tolerances.

In order to make the procedures and device parts used simpler andclearer, the positioning method and positioning system are basedhereafter only on a three-dimensional measuring machine and a workpiecewhich is positioned in the space arranged within the range of themeasuring machine and which is held by means of corresponding seatingcolumns known per se. When the system is used with other machines, theaverage person skilled in the art can adapt to the operation and devicesaccordingly. Ideally, the number of components of the positioningelements to be used is to be kept as small as possible, on the one handfor reasons of cost and, on the other hand, so as to avoid inaccuraciesbeing added together into relatively large positioning inaccuracies ormeasuring inaccuracies. One of the couplings to be used according to theinvention, both on the head of the measuring machine, being insertedinto the device used for the tracer, and on the head of the seatingcolumn, consists essentially only of the following elements: an adapterfor coupling to the machine or the base of the seating column, anintermediate member allowing the coupling to move through 360°, althoughthis degree of freedom in the X-Y-axis can be fixed by means of anyangular lock, and a second coupling part which is to be arrangedpivotally movably on this coupling part of the coupling and which isheld so as to be pivotally movable relative to the first coupling partover somewhat more than +/−90° in a vertical plane relative to the axisof the latter, the pivot axis necessary for this purpose likewise beingcapable of being secured in a predefinable angular position. Lastly, itis also necessary, on this second coupling part, to have a fixingelement arranged on the free end of the latter, so that an alignment ofthe complementary coupling part with the coupling of the seating columncan be maintained in a defined angular position. Such fixing may be asleeve which covers a defined spacer piece of known length between thetwo free coupling parts, or it may be a magnetic holding means, so thatthe coupling parts can be magnetically coupled to one another. Thespacer piece used may, for example, be an accurately dimensionedcylindrical column provided, at both ends, with annular grooves, atwhich corresponding locking means of the coupling parts can hold thisspacer piece. Ideally, the first coupling part and the adapter consistof a stepping motor or servomotor, in which one disk can turnrotationally relative to a second disk over a presettable degree ofangle, for example according to an electric signal generated in thecomputer of a measuring machine. This stepping motor is provided with aforked piece at its end facing away from the machine, the forked piecehaving, at its ends, a pivot axis which receives in a pivotally movablemanner a second motor designed in a similar way to the first steppingmotor. This second motor is arranged pivotally movable about the pivotaxis between the fork ends and, at its free end, carries a magneticplate, for example a permanent magnet or else an electromagnet. If theseating is equipped in the same way, the magnets can be coupled to oneanother, so that the pivoted motors are coupled to one another, at thepredefined angle, along the calculated intersecting axis. The joints ofthe couplings can then be fixed in this position, and the magneticholding means is then separated. Since the measuring machine has lockedon to the correct coordinate point, the seating column has been brought,after pre-adjustment, into a position such that, after coupling with thecounterpiece, the pivotally movable motor is located on the seatingcolumn in the correct position, so that a workpiece can be supported atthe desired location, with the seating surface being in the desiredposition. If appropriate, a seating means is placed onto the magneticplate, said seating means being adapted to the contour of the workpieceand bridging a possible distance between the range of the seating columnand the actual seating point of the workpiece.

Insofar as stepping motors of this kind cannot be used for the seatingcolumn and/or for the measuring head, for example because they are tooexpensive or too heavy, an auxiliary device, an adjusting device, can beused, which is positioned at a selectable reference location orreference point in the working space on the base plate. An adjustingdevice of this kind could then be equipped, in the same way as themovable seating column, with corresponding stepping motors, while theseating columns in the measuring machine itself have manual couplingsystems. In this case, as described above, for this purpose themeasuring machine is first used to determine the position of theworkpiece in the working space, to calculate a reference plane and todetermine an axis intersecting the reference plane. The adjusting deviceis then preset accordingly by the stepping motors being moved to theangular position complementary with the workpiece position, or itsreference plane, and the intersecting axis. In a further step, one ofthe couplings described, but in a version to be operated manually, ispositioned in the measuring head of the measuring machine, instead ofthe measuring tracer. This measuring head is then moved to a referencepoint of the working space, said reference point being located at adefined distance from the head face of the pivotally movable motor ofthe adjusting device. At the same time, the position of the intersectingaxis at the reference point is approached and the coupling on themeasuring head is then connected manually with the adjusting device, andthe coupling, that is to say its pivot axis and axis of rotation, issubsequently fixed, so that the coupling no longer has any degrees ofrotational freedom at the measuring point. After this preadjustment ofthe coupling, the measuring head is then moved to the desired locationin the working space, and, as described above, the supporting column ispositioned there, by the couplings being connected to one another andtherefore the intersecting axis also being fixed in its X-Y-Z axialposition on the supporting device. The couplings are then uncoupledmanually, and the support means for the workpiece is inserted into thefree coupling end of the supporting column.

If an adjusting device of this type likewise cannot be used, for examplebecause the baseplate is very small or the stepping motors are still tooexpensive, in this case, too, the adjusting device may be equipped witha manual coupling device, either in the manner of couplings which arealso present on the supporting column or on the measuring head or inthat the adjusting device consists merely of a reference plinth which,in two or four reference directions, carries reference balls which canbe connected by a centering means, in the manner of a union nutconnection, to a couplable spacer piece relative to the measuring head.In this case, as described above, the measuring machine approaches thereference point of the adjusting device, and the centering elementarranged on the reference ball with play, but positively, is thencoupled to the manual coupling of the measuring machine by means of theunion nut connection, using a spacer piece, and, in turn, the degree ofrotational freedom and the degree of pivoting freedom are blocked on themeasuring machine by appropriate locking means. Thereafter, as describedabove, the supporting column can be set up according to the model ofaxial inclination at the coupling of the measuring head.

Depending on the desired degree of automation or the outlay for suchpositioning systems according to the invention, both the measuringmachine head, the supporting column and/or an adjusting device may beprovided with an electrically or manually adjustable and lockablecoupling, and the necessary angular settings on the couplings may becarried out manually or by electric control. In all cases, however, areference plane or surface for the workpiece seating at a distance fromthe vertical axes of the supporting column or of the adjusting device,on the one hand, and of the measuring head, on the other hand, mustfirst be defined according to the geometric dimensions of the supportingcolumns and support means used and with respect to the intersecting axiswhich, in the simplest case, is orthogonal to the reference plane. Theright-angled axial position (in relation to a reference plane centrallybetween the vertical axes) is obtained automatically, using spacerpieces with parallel annular grooves and manually operable couplings ofidentical design.

The supporting element or support means, to be inserted into thesupporting column, for the workpiece has, in relation to the supportingcolumn, a reference plane, for example the top side of the supportmeans, which is plane-parallel to a surface of the supporting column, sothat, in the case of manual variation of the support means, the latteris not rotated or tilted out of the desired spatial position.

In a particular embodiment of the support means, the latter may beprovided with a complementary surface to the workpiece surface, but thissupport means also acquires a further degree of rotational freedom, sothat a workpiece contour deviating with respect to the reference planecan be taken into account. This is particularly expedient in thepositioning of workpieces, such as pipelines or the like, which do nothave two-dimensional seating edges and the support means therefore hasto be designed as a multipoint support. It could be the same if theworkpiece surface is provided with a three-dimensional structure at theseating point and the surface of the support means has to be aligned inthe same way. If the surface of the support means has to be pivoted forthis purpose, a bearing with a degree of rotational freedom is arrangedon the support means itself, if appropriate with an indicator for theangular position or the arc dimension.

If nonmagnetic coupling parts are used for the above-described spacerpiece or the support means, it is necessary for said coupling parts tobe guided accurately, which is appropriately carried out by means of acorresponding design of the free end of the coupling part of therespective coupling. Since the spacer piece itself is to have a fixeddimension, adjustable coupling elements cannot be mounted there. Forthis reason, at least the coupling of the supporting column or thecoupling on the measuring head must be equipped with a sleeve engagingover the spacer piece or with elements acting in a similar way, so thatthe spacer piece can be coupled and uncoupled. In order that the exactdistances between the coupling parts can be adjusted with repetitiveaccuracy, the spacer piece may preferably be provided with annulargrooves, in which locking means for the sleeves to be pushed into thespacer piece or coupling parts can be accurately fixed. The spacer pieceis held centrally in the direction of the intersecting axis byappropriate centering means within the coupling parts.

Further advantages and details of the device according to the inventionand of the positioning method may be gathered from the followingdescription with reference to exemplary embodiments. By means of themeasuring machine equipped in this way, a measuring point or a measuringsurface can be approached with an accuracy of less than 0.1 mm and theworkpiece positioned with corresponding accuracy.

The invention is described in more detail below with reference to apartly diagrammatic and partly concrete drawing in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a positioning device with adjusting device, tool and spacerpiece;

FIG. 2 shows a positioning device with a supporting column, as avertically adjustable device, as well as a tool and spacer piece,according to FIG. 1;

FIG. 3 shows the device according to FIG. 2 in the coupled state;

FIG. 4 shows the device according to FIG. 2 after the supporting columnhas been fixed;

FIG. 5 shows a supporting column with the support means to be inserted;

FIG. 6 shows a second form of the adjusting device and a second form ofthe tool;

FIG. 7 shows a third form of the adjusting device or supporting column;

FIG. 8a shows a concrete form of the adjusting device according to FIG.1 in section;

FIG. 8b shows a concrete second form of the positioning system, similarto FIG. 3, in section;

FIG. 8c shows a concrete alternative plinth for a positioning system;

FIGS. 9a-c shows a second and third support means with clampingelements; and

FIGS. 10d-f shows different forms of support means.

Identical or identically acting components are given identical referencesymbols below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A positioning system according to FIG. 1, the parts of which consistessentially of light metal, shows the base of an adjusting device 2provided with a coupling 1 which can be coupled via a spacer piece 3 toa coupling 4 of a tool/machine. A stationary part 11 is provided with aclamping ring 12, by means of which a shaft 13, rotatable through 360°with the degree of freedom F 1, can be locked at any desired angle ofrotation relative to the fixed part 11. The shaft 13 is connected to acoupling part 14 which is pivotally movable about the locking means 17and which has a degree of freedom of about 180°, so that an angle ofabout +/−90° relative to the longitudinal axis of the part 13 can be setbetween the shaft 13 and the coupling part 14. Arranged on this couplingpart 14 is a part 15 which is designed in the manner of a union nut orslip-over sleeve and which is movable, in the position of rest, in thedirection of the locking means 17 or the intermediate joint 13, but, onthe other hand, can be slipped over the spacer piece 3 and connected tothe latter by the locking means 18. The spacer piece 3 is secured, onthe other hand, by a locking means 48, designed identically to thelocking means 18, in a slip-over sleeve 45 which is designed in asimilar way to the sleeve 15. The sleeve 45 can, in turn, be displacedaxially on the coupling part 44, so that the spacer piece 3 can beextracted or inserted between the sleeves 45 and 15. The coupling part44 forms, with a further part 43 connected in a pivot axis of thelocking means 47, an angle which can be designed to be about +/−90°relative to the axis of the part 43 according to the degree of freedom F2 which is exactly the same as the equivalent degree of freedom on theadjusting device 1, 2. The part 43 is held on the machine side via anadapter 41. The part 43 is capable of being moved with F 1 in rotationthrough 360° relative to the axis of the adapter 41, but can be stoppedby locking means 46 on the clamping ring 42. The part 4 may also bedesignated, as a whole, as a tool, machine head or measuring head withcoupling.

The parts of the positioning system which are illustrated in FIG. 1 makeit possible to use a tool or measuring device, with the aid of ameasuring machine which can be connected to the journal 40 with theadapter 41, in order to calculate positions of supporting columnsaccurately in space with the aid of the adjusting device and tool andsubsequently to align them. For this purpose, the measuring machine isbrought to the illustrated position relative to the base 2, thepreviously calculated spatial position of the axis being symbolized by aconnecting line between the axes of the locking means 17 and 47,previously also called an intersecting axis. The spacing of the axes ofthe components 41 and 13 is determined by the spacer piece 3 having afixed length and by the overall lengths of the corresponding couplingparts 14 and 44.

After the measuring machine together with the tool 4 has been moved intothe position illustrated, the spacer piece 3 is coupled between theadjusting device 2 and the tool 4 and the locking means 48 and 18 aretightened, so that an accurate spacing of the vertical axes or anaccurate length of the relevant portion of the intersecting axis isensured. The locking means 46 is then actuated, in order to block thedegree of freedom F 1, and the fastening means 47 is tightened, in orderto block the degree of freedom F 2, after the degree of translationalfreedom, illustrated by the arrows parallel to the intersecting axis,has previously already been restricted by the fixing of the spacer piecewith the aid of the locking means 18, 48.

FIG. 2 shows, then, that the locking means 18 of the adjusting device(FIG. 1) or of the corresponding coupling part has subsequently beenreleased, the annular groove 31 of the spacer piece 3 having been freed,so that the spacer piece 3 has been moved by the tool 4 relative to asupporting column with the coupling 6 and base 5. The base of thesupporting column has been preadjusted in the X- and Y-directions anddisplaced on a base plate (FIG. 8b) in such a way that, within thecoupling 6 of the supporting column, a first height adjustment (FIG. 3)can take place in the direction Z of the coupling axis 63 andsubsequently the column with the coupling part 64 can be pushed over thespacer piece 3, so that the locking means 68 on the coupling part 64 canengage into the groove 31 of the spacer piece 3 and accurately adjustthe connection between the workpiece and supporting column. For thispurpose, it is initially unimportant whether the receptacle (part 64)for the spacer piece 3 is movable along the intersecting axis (arrow)and can be pushed over the spacer piece or whether, according to FIG.8b, the receptacle (part 65) for the spacer piece is fixed on thesupporting column and is not designed as a slip-over socket. Theadvantage of this is that the version according to FIG. 8b is moreaccurate and allows less play.

The supporting column has a stationary part 61 and a clamping ring 62,in which the shaft 63 is movable in rotation according to the degree offreedom F 1 and, at the same time, is adjustable in terms of its height,as shown by the arrow in FIG. 3. The coupling parts 63, 64 are pivotablevia the intermediate joint or the locking means 67, movement beingpossible with a degree of freedom F 2 of +/−about 90°, preferably 2 to5° in any direction. After the supporting column 5, 6 is coupled to thetool 4, as illustrated in FIG. 3, the locking means 67 for theintermediate joint and a locking means, not illustrated, for theclamping ring 62 are actuated, so that the two degrees of freedom F 1and F 2 are blocked and the part 64, with its axis, more specificallythe intersecting axis defined by the axes of the parts 44, 3, 64, isfixed. During the mounting of the supporting column, the measuringmachine with the adapter 41 was moved accurately into the positionobtained as a result of the intersecting axis, and into the referenceplane, defined by the spacer piece or, for example, its end faces, at adistance from the vertical axis of the adapter.

FIG. 4 shows that the locking means 68 is then released, so that themeasuring machine together with the tool 4 and with the spacer piece 3can leave the supporting column. Alternatively, the spacer piece 3 caninitially remain in the supporting column and can be extracted later.

FIG. 5 then shows that this spacer piece is replaced by a support means100. The latter is equipped with a surface, its top side 103,complementary with the seating of the workpiece, as well as with ajournal 102 and a groove 101 which can be fixed in the exact desiredposition by the locking means 68.

FIG. 6 shows, instead of an adjusting device 1, 2, an alternativeadjusting device 7 comprising a cross slide 72 arranged on a base platewhich is not illustrated. Seated on the cross slide 72 are referenceballs 71 provided with a union nut sleeve 73 for a spacer piece 33. Thetool 8 is designed, here, as a sleeve 80 which can be pushed over themeasuring head 81 having a tracer 82. The sleeve 80 has a journal 83, onwhich are provided a rotational coupling unit 84, with a degree offreedom of 360° about the vertical axis of the measuring head, and aforked piece 85 which is arranged on the coupling part and which itself,in turn, carries a pivoting unit 86 pivotable through +/−95° about thepivot axis 87. Flanged to this pivoting unit 86 is a coupling part 88provided with a box sleeve 89 for connecting this coupling 88 to thespacer piece 33. In this case, the pivotings of the units through 360°and through +/−95° are executed by means of electrically operatedstepping motors or servomotors which can be controlled by the computerof the measuring machine or the machine moving the measuring head 81,with the result that the corresponding pivot angles or angles ofrotation can be transmitted directly from the software program to thepositioning means illustrated in FIG. 7. Since the adjusting device 7 isequipped with the balls 71, the axis of the measuring head 81 is freelymovable relative to these balls 71 in the way illustrated, specificallywith two degrees of rotational freedom, so that the connection from theball center to the pivot axis 87 ultimately represents the intersectingaxis according to the invention.

FIG. 7 shows an alternative adjusting means instead of the cross slide72 and of the adjusting head equipped with balls, which alternativeadjusting means can be arranged at a predetermined location on ameasuring machine table or a baseplate 800. To that extent, the deviceparts 800 to 880 represent a mirror-symmetric version of theabove-described design of the tool bearing the reference numerals 80 to88. Fixed on the machine table 800 is a base unit 810 of an adjustingmeans, in which a programmable stepping motor is arranged so as to bemovable through 360°, said stepping motor being adjustable over apredeterminable angle, for example with a limit switch function. Arotary head 840 holds in a fork 850, at the joint 860, a further rotaryhead with an integrated programmable stepping motor 870 which ispivotable through +/−100° about a rotary journal, as indicated by theangle scale marks. The stepping motor 870 carries, on its head side, amagnet 880, by means of which, instead of the above-described couplingparts for a spacer piece 3, this spacer piece is accurately fixedmagnetically on the adjusting head. Alternatively, of course, thecoupling means (FIG. 1) already described as part 1 may also be used onsuch a stepping motor or pivoting device.

FIG. 8 a shows in concrete form, as compared with FIG. 1, an adjustingdevice having the parts 1 and 2. The part 2 comprises, here, a baseplate21 and a fixing means 22 for the stationary part 11 of the coupling 1.Two axial and radial bearings 111 are fixed on the threaded journal 131in a sleeve shaped housing 110 by means of a spring ring 113 and a nut132. The threaded journal 131 belongs to the shaft 13 which is thusmounted freely movably in rotation, but, on the other hand, accuratelyand free of play, in the housing 110. The clamping ring, designated as awhole by the numeral 12, consists of a slotted torus 120 which is fixed,on one side, to the housing 110 by means of screws 121 while, on theother side, a clamping screw 16 passes through the slot 122, in order toblock the degree of rotational freedom of the shaft 13. The shaft 13terminates in the half shaft or the journal part 133 which is connectedto a complementary journal part 141 over the part 14 by the lockingmeans 17. The locking means comprises a wing nut 171 having a slidingjournal 172 which terminates in a threaded journal 173. The slidingjournal 72 is seated in a drilled bush 174 which bridges the two journalparts 133, 141, while said sliding journal 172 can be screwed into athreaded bore of the journal part 141, so that the coupling-side head ofthe wing nut 171 secures the journal part 133 by clamping against thejournal part 141. The part 14 terminates in a central guide part 142having about half the diameter of the largest dimension of the journal14. Fixed to the head of the guide part 142 by means of a screw 143 is acollar disk 144, so that the sleeve 15, with its collar 151 sliding onthe guide 142, cannot fall off from the part 14. The locking means 18provided with a wing nut 181 having a threaded journal 182 passesthrough the sleeve 15 in a thread, not illustrated, and thus, accordingto FIG. 1, a spacer piece 3 can be fixed in the groove 31.

FIG. 8b shows, in a design similar to that of the adjusting device, adevice which is designed as a supporting column, the fixed part 5comprising a plinth (base unit) 51 with an internal thread 510 which iscapable of being fixed on a baseplate 21 with the aid of a clampingdevice 511 or 512, 513. If required, an extension 52 having an externalthread can be screwed into this base unit 51, into the thread of thelatter. The steel plates 53, 54, which are fixed by means of screws 531,541, define surfaces for applying fork wrenches, so that the threadedparts can be tightened relative to one another. The extension 52 may bedesigned at any desired column height. The extension 52 also carries aninternal thread 521 and can receive therein the stationary part 61,having an external thread 611, of the coupling 6. The stationary part 61of the coupling consists of a sleeve 610 with an inner guide bush 612for the shaft 63 which is movable in the guide bush 612 both in rotationand in the axial direction of the shaft. The translational movement ofthe shaft in the Z-direction is limited by a spring ring 631 ininteraction with the bash 612. The largest diameter 630 of the shaft 63can be fixed with a clamping effect, both in the direction of rotationand in the direction of translational movement, with the aid of theslotted ring 62 as well as the locking means 66 with the wing nut 661.The journal 632 of the shaft 63 is locked no:positively, in the pivotangle position of said shaft, with a similarly designed journal 651 bythe locking means 67 which is identical to the locking means 17. Thepart 651 may be designed in a similar way to the part 14 or 64, but itis more advantageous to dispense with a slip-over sleeve similar to thesleeve 15 and, instead, design the part 651 with rotationally symmetricinner centering as a flange of said part. A spacer piece 3 with grooves31 can be fixed in this centering of the flange by a correspondinglocking means 68 which is designed to be identical to the locking means18. It can be seen clearly that the pin 682 bears with its head on aflank of the groove 31 and thus ensures that the spacer piece 3 isclamped, free of play, relative to the locking device 48 in the groove32 of said spacer. The sleeve 45, coupling part 44 and locking means 47are designed in the same way as the sleeve 15, coupling part 14 andlocking means 17. The locking means 47 clamps to the coupling part 44 ashaft piece 43, in which is centrally fixed by means of a screw 432 ashaft 431 which, on its larger collar 433, supports an adapter 41 in arotationally movable manner. The adapter 41 terminates in a connectingthread 40 connecting with a machine tool or measuring machine. Theadapter 41 is connected to a clamping ring 42 by means of a screw 421.This clamping ring 41 is slotted and can be clamped by the locking means46 by means of a wing nut illustrated, so that the rotational movementof the shaft 431 in the adapter 41 is blocked. On the other hand, as hasalready been described above, the part 43 can be connected to the part44 so as to be pivotally movable about the locking means 47, previouslyalso called an intermediate joint. The adapter 41 or the connectingthread 40 may, if appropriate, be adapted to a receptacle of a measuringmachine head in such a way that a signal connection from the computer ofthe measuring machine or an electric line for drive energy can be fedinto the tool generally designated as the part 4.

The purpose of these connections is, for example, to make it possible toutilize further the collision sensors conventional in the case ofmeasuring tracers or to drive energy for the stepping motors, whichtogether form this tool 4 or are parts of this tool, or to transmitregulating commands to these.

FIG. 8c shows an alternative to the plinth 51 to be clamped or theclamping device 511 to 530 according to FIG. 8b on a baseplate 21. Thebaseplate 21, a plane clamping table with grooves or holes at gridintervals, serves for supporting and fixing the plinth 51 a of a columnillustrated merely by the part 61. The foot plate 514 can be positionedfreely on the baseplate 21. Said foot plate 514 has a perforation 519which is partially congruent with the long hole 517 in the intermediatering 515. The intermediate ring 515 and an adapter ring 518 are both orindividually freely movable in rotation, in the direction of the arrow,relative to the foot plate 514 and the column part 61, respectively. Itis thereby possible for the screw 516 to be displaced in the directionof the arrow in the long hole 517 and at the same time in theperforation 519, until it can engage in a complementary nut, perforatedblock or tenon block, not illustrated, in the baseplate 21 and thus fixthe column.

FIG. 9a shows a clamping means, provided as a whole with the numeral 9,which is coupled to a support means 320 and which has a similarappearance to the spacer piece 3, in particular is provided with anannular groove R, so that the support means 320 can be held with thelocking means 68. The actual supporting surface for seating a workpieceis designated by 321.

FIG. 9b shows the clamping means 9 with the clip 91 for engaging round asupport means 310 to 370 (FIG. 10), the support means being fixed to theclip by means of the screw 911. A first lever 92 has a multiplicity ofholes for a column 94 which is connected to the lever 92 in a pivotallymovable manner by means of a rotary joint 93. The lever 94 has itself,at its free end, a pivoting joint 941 with 360° of rotational freedomand is coupled, in the rotary joint, to a claw 95 which, at its freeend, carries a clamping bolt 96 which can be displaced along the claw95, within the long hole or slot 951, in such a way that said clampingbolt can be adjusted, in each case via the clip 91, according to theoffset of the center of a rotation 93.

FIG. 9c shows another possibility for clamping workpieces with the aidof a tensioner 97 which is fastened on the head 890 of a device 870(FIG. 7) by means of screw. The tensioner 97 is built on the base 973,the base being itself fastened to the head 890 (in a similar way to FIG.7). Depending on the movement of the lever 972, the claw 971 or thetensioner 97 itself can be moved in the direction indicated by thearrows and, thus adapted, can in each case find the correct clampingpoint for the claw 971 relative to the support means 330.

FIG. 10a-10 f show various support means 310-370 which can be insertedinto the coupling part 652, and the support means 310 can be lockedthere, in its annular groove R, by the locking means 68. If necessary, afurther clamping means can be coupled to the annular groove 313, withthe aid of which clamping means the multidimensional support 311 of aworkpiece not illustrated, for example a pipeline or a prism, can beadditionally fixed. 312 designates a pivot mounting with angle scalingor a vernier, said pivot mounting making it possible for the journals ofthe multidimensional support points 311 to be adapted additively to theposition of the workpiece after the support means 310 has been clamped.

The further support means for use with the supporting columns 5, 6 areshown in a similar way, the respective surfaces 331 to 371 being adaptedto the corresponding contour of a workpiece. Thus, for example, annularworkpiece faces can be supported by means of the surfaces 351 and 361,while the surface 341 makes it possible to use any desired supportingcontour adapted to the workpiece contour. At the same time, in thiscase, the circular top surface or underside of the support means mayserve as a reference plane, while the vertical center line of thissupport means coincides with the intersecting axis.

What is claimed is:
 1. A method for accurately positioning a device for temporarily fixing a workpiece in a three-dimensional working space of known coordinates, the workpiece requiring a multidimensional seating, use being made of a machine that is computer-guided and designed to be capable of approaching all coordinates with a tool, and of a vertically adjustable device freely movable on a baseplate, the device being connected in a rotationally movable manner to a first coupling and the tool being connected in a rotationally movable manner to a second coupling, each coupling comprising at least two coupling parts which are connected by means of lockable and pivotally movable intermediate joints, and the two couplings being temporary couplable indirectly to one another, the method comprising the steps of: a) determining a spatial arrangement of the multidimensional seating in the working space with a computer; b) determining a reference plane of the seating and an axis intersecting the reference plane; c) fixing a coupling part of the second coupling to the tool, after the intermediate joint of the second coupling has been secured in the direction of an intersecting axis; d) moving the tool toward the intersecting axis at a defined distance from the reference plane; e) connecting a further coupling part of the second coupling to a coupling part of the first coupling which is approximately preadjusted, and subsequently fixing the coupling parts of the first coupling in an axial direction defined by the second coupling; f) securing the device on the baseplate and in terms of its height; and g) uncoupling the couplings and inserting support means, complementary with the seating on the workpiece, into a free coupling part of the first coupling.
 2. A method as defined in claim 1, wherein step c includes using manually one of rotationally and pivotally movable couplings, the fixing in step c initially including moving the tool, in an intermediate step, to a reference point of the working space which is located on an axis parallel to the intersecting axis, at a defined distance from an adjusting device positioned at a defined location on the baseplate and having the first coupling and, after the adjusting device has been coupled to the second coupling, securing the intermediate joint of the second coupling, step e) including a first substep of securing the intermediate joint of the first coupling after indirect connection of the coupling parts of the two couplings.
 3. A method as defined in claim 1, including holding each of the couplings so as to be pivotally movable through 360° in a plane parallel to the baseplate and so as to be pivotally movable through about +/−90° in a plane vertical thereto.
 4. A method as defined in claim 1, wherein an electrically adjustable coupling is used, steps c and e including positioning the coupling in at least one plane in relation to a solid angle of the intersecting axis by electric signals with aid of coordinates and angle values determined by a computer.
 5. A method as defined in claim 1, including temporarily connecting the couplings on the device and the tool with a spacer piece of known length for compensating for at least one of an angular difference and a system related distance from the reference plane.
 6. A positioning system for accurately positioning a support device for temporarily fixing a workpiece in a three-dimensional working space of known coordinates, the system comprising: a machine; a computer operatively connected to the machine for control thereof, the machine including a triaxially movable head for one of a tool and a measuring tracer; a baseplate; devices, freely movable and lockable on the baseplate so as to form a support column for the workpiece to be process; and a coupling system for temporarily coupling the head and the support column for accurate positioning the support device on the support column under a seating of the workpiece, the coupling system comprising a respective identically acting coupling on the head and on the support column, each coupling having two coupling parts and an intermediate joint that connects the coupling parts together so that one of the coupling parts has a degree of rotational freedom of 360° and another of the coupling parts has, perpendicularly thereto, a degree of rotational freedom of about 180°, the coupling system further including locking means for securing the coupling parts relative to one another and relative to the head and the support column at a selectable angle.
 7. A positioning system as defined in claim 6, and further comprising an adjusting device, positionable on the baseplate, for alignment of the coupling on the head.
 8. A positioning system as defined in claim 7, wherein the adjusting device has one of an identically acting coupling and a coupling having a reference ball with centering means, so as to form a union nut in connection with a part to be coupled.
 9. A positioning system as defined in claim 6, wherein the support column has support means which, in a desired position, has a coupling side seating surface parallel to a reference plane of the workpiece seating.
 10. A positioning system as defined in claim 9, wherein the support means has a fixed length.
 11. A positioning system as defined in claim 9, wherein the support means has a workpiece side with a surface complementary to a contour of the seating of the workpiece.
 12. A positioning system as defined in claim 9, and further comprising clamping means for the workpiece, the support means being connectable to the clamping means.
 13. A positioning system as defined in claim 6, wherein each coupling has: a first coupling part with a central guide for a part to be coupled, a socketlike sleeve part and a lock for a connection of the sleeve part to the part to be coupled; a second coupling part with a central shaft and an adapter arranged so as to be freely movable in rotation through 360° thereto an lockable, for a connection to one of a device and a machine; and an intermediate joint that connects the coupling parts in a pivotally movable manner, the joint having locking means for securing the coupling parts at an angle relative to one another in a range of about +/−90°.
 14. A positioning system as defined in claim 13, wherein at least one of the sleeve part and the adapter is a sleeve capable of being slipped over the parts to be coupled, the sleeve part being longitudinally movable parallel to an axis of the central guide, the adapter being rotationally movable relative to the guide.
 15. A positioning system as defined in claim 13, wherein at least one of the coupling parts is one of a stepping motor and a servomotor which is movable in rotation over a predeterminable degree of angle. 